Extraction ball-mill tumbler

Figure 1. Ball-mill tumbler extraction scheme...

Ball-Mill Tumbler Extraction. To avoid unnecessary cost, inconvenience, and hazards involved in extracting large numbers of sediment samples with boiling solvents (6), we have investigated alternative procedures. Ideally, a suitable procedure should extract efficiently and reproducibly and be simple, safe, and convenient. In particular, we needed a method that used minimal benchtop or hood space could... 

Figure 5. Recovery [log (ppm dry weight)] of nonalkylated PAH compounds for methylene chloride reflux, soxhlet, and ball-mill tumbler extraction methods...

The results of the three extraction experiments for PAH compounds are shown in Figures 5, 6, and 7. The concentrations of nonalkylated parent PAH compounds at m/e 178, 202, 228, 252, 276, and 278 were determined by GC-MS analysis. These concentrations (corrected for instrument response) are shown in Figure 5. The results showed that the soxhlet extraction and the CH2C12 reflux were approximately equal in their ability to extract these PAH compounds, while the ball-mill tumbler extraction method was only about 72% as efficient as the other two methods. PCDs obtained from the different extraction methods are shown in Figure 6. This figure demonstrates the consistency of each method for extracting nonalkylated PAH compounds and shows the close similarity... 

We have derived an extraction method that retains the convenience of the ball-mill tumbler for large numbers of extractions, and have investigated various solvent systems for improved recoveries. Preliminary results indicate that a tumbler extraction using methanol and dichloro-methane recovered hydrocarbons from an intertidal sediment as efficiently as the soxhlet technique (12). This report describes improvements in our tumbler procedure and compares it with three boiling-solvent procedures (10,13,15). 

The results of the three PAH extraction methods are shown in Figure 5. The soxhlet extraction (I) and CH2C12 reflux (III) were about equal in their ability to extract PAH compounds. The ball-mill tumbler (II) was only 72% as efficient as the other methods. A two-way, crossed-factor analysis of variance on the log-transformed data was used to test whether or not there were significant differences in the amount of parent compounds returned by these three methods. An F-test indicated signifi-... 

Figure 6. Comparison of PAH PCDs for replicate extractions by methylene chloride reflux, soxhlet, ana ball-mill tumbler methods...

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